1. Field of the Invention
This invention relates to an ultrasonic wave generator having a vibratory member of a hollow cylindrical body and wherein, at a connecting portion of a vibratory member and a mechanical vibration amplifying member, an increased thickness portion projecting from the two members is integrally formed.
2. Description of the Prior Art
According to exemplary prior art ultrasonic wave generators, an ultrasonic wave horn is secured to a piezo-electric transducer or a magnetostrictive transducer whereby an ultrasonic wave is generated from the end face of the horn, with the amplitude of the wave being amplified by means of the horn, or alternatively an ultrasonic wave is generated from the cylindrical surface of a cylindrical ultrasonic wave transducer. With the aforenoted ultrasonic wave horn, it is imperative that the cross-sectional area of the tip portion of the horn be decreased in order to amplify the amplitude of an ultrasonic wave, and consequently, ultrasonic vibrations having a large amplitude may only be obtained from a very limited area of the ultrasonic wave generator. On the other hand, an ultrasonic wave generator using an ultrasonic wave transducer having a cylindrical configuration facilitates the generation of an ultrasonic wave from a large area of the aforenoted cylindrical surface, however, it fails to amplify the amplitude of an ultrasonic wave by means of an ultrasonic wave horn or the like, and consequently, the result is that an ultrasonic wave of a large amplitude is not in fact generated.
One of the attempts for avoiding the aforenoted disadvantages confronted with the aforenoted prior art ultrasonic wave generators, which has been proposed by the present inventors, is an arrangement whereby an ultrasonic vibratory member of a hollow cylindrical body, having a uniform wall thickness, has its outer circumferential surface secured to the tip of an ultrasonic wave horn which has also been developed by the inventors, whereby the aforenoted vibratory member is subjected to vibration due to the ultrasonic vibrations having an amplified amplitude, thereby generating an ultrasonic wave from its cylindrical surface (See Japanese Patent Application No. 36506/1973, and United States Patent Application Ser. No. 453,987, filed Mar. 22, 1974), now abandoned.
According to such ultrasonic wave generators, the vibratory member of the hollow cylindrical body generates ultrasonic vibrations in a direction perpendicular to the axis of the cylinder whereby a large area of the inner and outer circumferential surfaces of the hollow cylindrical body may be utilized as the vibration-generating surfaces, while the vibratory member is subjected to flexural vibration, thereby generating an ultrasonic vibration of a large amplitude.
However, this attempt still suffers from shortcomings in that because the cost of manufacturing the vibratory member of the hollow cylindrical body having a uniform wall thickness, and the horn, are high if they are manufactured as an integral construction, they are in fact fabricated separately whereby the vibratory member is subsequently secured to the tip portion of the horn by means of suitable fastening means, such as, for example, a bolt. In this condition, however, during long periods of operation with a large amplitude of vibration, insufficient mechanical strength and fatigue cracking, within the coupling portion of the vibratory member and the tip portion of the horn, is exhibited due to the existence of the poor coupling by means of the bolt at the small circular cross-sectional area of the aforenoted coupling portion. In addition, intimate contact between both members to be coupled together is required within such a device when coupling the vibratory member of the hollow cylindrical body to the tip portion of the horn, and this substantially increases the number of man-hours required for the manufacture of the ultrasonic wave generator, and the same also exhibits poor reliability.